gpio: sl28cpld: Replace irqchip mask_invert with unmask_base

Remove use of the deprecated mask_invert flag. Inverted mask
registers (where a '1' bit enables an IRQ) can be described more
directly as an unmask register.

Signed-off-by: Aidan MacDonald <aidanmacdonald.0x0@gmail.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

gpio: sl28cpld: convert comma to semicolon

Replace a comma between expression statements by a semicolon.

Signed-off-by: Zheng Yongjun <zhengyongjun3@huawei.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>

gpio: Add support for the sl28cpld GPIO controller

Add support for the GPIO controller of the sl28 board management
controller. This driver is part of a multi-function device.

A controller has 8 lines. There are three different flavors:
full-featured GPIO with interrupt support, input-only and output-only.

Signed-off-by: Michael Walle <michael@walle.cc>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>